<?php
//索引+关联 = 混合数组
$arr = ['java' => 10, 50, 'python' => 20, 'html' => 30, 'mysql' => 40, 'php' => 50];
$arr[] = 100;
$arr[100] = 200;
$arr[] = 300;
echo '<pre>';
print_r($arr);

echo $arr['mysql'], '<br>';